<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<script type="text/javascript">
			function Student(){
				this.name = "tom";
				this.age = 20;
			}
			var stu = new Student();
			with(stu){
				console.log(stu.name,stu.age);
			}
			
			delete stu.age;
			console.log(stu.name,stu.age);
			
		</script>
	</head>
	<body>
	</body>
</html>
